Endogenous Modulation of Cochlear Injury

描述（由申请人提供）：顺铂是一种广泛用于治疗恶性肿瘤的强效化疗药物。副作用，如耳毒性损害癌症幸存者的生活质量。顺铂增加耳蜗中活性氧（ROS）的形成。NADPH氧化酶的一种独特的亚型NOX-3存在于大鼠耳蜗中。这种酶会产生超氧化物自由基，破坏外毛细胞（OHC），导致听力损失。ROS可以激活耳蜗基因，这些基因可能是保护性的，也可能是有害的。保护性分子可能包括一种新的蛋白质，肾损伤分子（KIM）-1。顺铂在肾脏中诱导。这种分子可以增强近端小管细胞的修复和再生。我们的实验室是第一个在耳蜗中显示KIM-1及其被顺铂诱导的实验室。ROS可上调KIM-1的表达。目前尚不清楚这种蛋白质是否能保护耳蜗免受顺铂的侵害。顺铂引起的ROS也可能增加潜在有害的瞬时受体电位香草素1受体（TRPV1）的表达。NOX-3和TRPV1的激活可能会压倒耳蜗的抗氧化防御，导致细胞死亡。本申请中的实验寻求更精确地定义顺铂耳毒性的机制，以便找到使毒性最小化的方法。拟进行的研究将利用耳蜗细胞系（UB/OC-1）和大鼠平行研究来解决三个具体目标：1）研究耳蜗中顺铂激活NOX-3的机制; 2）确定KIM-1的表达是否赋予对顺铂耳毒性的保护并确定其诱导的潜在机制;研究TRPV 1是否参与顺铂耳毒性并确定其诱导机制。对于目标1，我们将在圆窗（RW）上全身施用抗氧化剂硫辛酸或短干扰RNA（siRNA），以阻断顺铂对NOX-3的激活。在目标2中，我们将使用信号分子抑制剂的RW应用，以观察它们是否参与KIM-1诱导;以及KIM-1 siRNA的RW应用，以观察顺铂耳毒性是否增加。对于目标3，我们将调查是否RW应用TRPV1拮抗剂，辣椒平，保护顺铂耳毒性。我们还将检查RW施用针对TRPV1的siRNA的效果，以观察这是否防止顺铂耳毒性。本研究为阐明顺铂耳毒性的机制和改善顺铂耳毒性的治疗方法提供了新的思路。顺铂会导致很大一部分接受这种药物治疗癌症的癌症患者听力损失。如果能发现一种治疗方法，既能预防听力损失，又不干扰顺铂的抗癌作用，这对癌症幸存者将大有裨益。这项研究旨在发现新的潜在治疗方法，以减少顺铂治疗癌症引起的听力损失的副作用。顺铂会导致很大一部分接受这种药物治疗癌症的癌症患者听力损失。

DESCRIPTION (provided by applicant): Cisplatin is a potent chemotherapeutic agent widely used to treat malignant neoplasms. Side effects, like ototoxicity compromise the quality of life of cancer survivors. Cisplatin increases formation of reactive oxygen species (ROS) in the cochlea. A unique isoform of NADPH oxidase, NOX-3, is present in rat cochlea. This enzyme generates superoxide radicals that can damage outer hair cells (OHCs), leading to hearing loss. ROS can activate cochlear genes that may be protective or harmful. Protective molecules may include a novel protein, kidney injury molecule (KIM)-1. It is induced in kidney by cisplatin. This molecule may enhance repair and regeneration of proximal tubule cells. Our laboratory was the first to show KIM-1 in the cochlea and its induction by cisplatin. ROS may up-regulate KIM-1. It is unknown whether this protein protects the cochlea from cisplatin. ROS resulting from cisplatin may also increase expression of potentially harmful transient receptor potential vanilloid 1 receptors (TRPV1). Activation of NOX-3 and TRPV1 may overwhelm cochlear antioxidant defenses, leading to cell death. Experiments in this application seek to more precisely define mechanisms of cisplatin ototoxicity in order to find ways to minimize toxicity. Studies proposed will utilize a cochlear cell line (UB/OC-1) and parallel studies in rats to address three specific aims to: 1) investigate mechanisms of NOX-3 activation by cisplatin in the cochlea; 2) determine whether expression of KIM-1 confers protection against cisplatin ototoxicity and to determine potential mechanisms of its induction; and 3) study whether TRPV1 contributes to cisplatin ototoxicity and to determine mechanisms of its induction. For aim 1, we will administer systemically the antioxidant lipoic acid or short-interfering RNAs (siRNAs) on the round window (RW) to block activation of NOX-3 by cisplatin. In aim 2, we will use RW application of inhibitors of signaling molecules to see if they are involved in KIM-1 induction; and RW application of siRNA for KIM-1 to see if cisplatin ototoxicity increases. For aim 3, we will investigate whether RW application of the TRPV1 antagonist, capsazepine, protects against cisplatin ototoxicity. We will also examine effects of RW administration of siRNA against TRPV1 to see whether this prevents cisplatin ototoxicity. This research could provide new insights into mechanisms of cisplatin ototoxicity and novel therapeutic approaches to ameliorate cisplatin ototoxicity. Cisplatin causes hearing loss in a large percentage of cancer patients who receive this drug to cure their cancer. It would be of great benefit to cancer survivors if a treatment could be discovered that would prevent hearing loss without interfering with the cancer killing effects of cisplatin. This research seeks to discover new potential treatments to reduce the side effect of hearing loss resulting from the treatment of cancer with the drug cisplatin. Cisplatin causes hearing loss in a large percentage of cancer patients who receive this drug to cure their cancer.